A 60-year-old asymptomatic man is found to have a leukocytosis when a routine CBC is obtained. Physical exam shows no abnormalities. The spleen is of normal size. Lab data includes:
Hgb: 9 g/dL
Peripheral blood smear shows a differential that includes 97% small lymphocytes.
The most likely diagnosis is
|A||Acute monocytic leukemia|
|B||Chronic myelogenous leukemia|
|C||Chronic lymphocytic leukemia|
Chronic lymphocytic leukemia
Chronic lymphocytic leukemia is the most common of all leukemias, with incidence increasing with age. Patients are usually asymptomatic, but may complain of weakness, fatigue, or enlarged lymph nodes. The diagnosis is made by peripheral blood smear, as mature small lymphocytes constitute almost all the white blood cells seen. No other process produces a lymphocytosis of this morphology and magnitude. The leukemic cells in acute leukemia are immature blast cells that are easily distinguished from the normal-appearing mature lymphocytes of CLL. Both chronic myelogenous leukemia and the leukemoid reaction associated with illness such as TB are associated with increased numbers of a variety of cells of the myeloid series (mature polymorphonuclear leukocytes, metamyelocytes, myelocytes, etc.). The peripheral blood is said to resemble a dilute preparation of bone marrow. The presence of basophilia would suggest CML.